3D environment for RL research in Academia
For example DeepMind [Lab] is not a standard or Open Source friendly


I'm not sure where you got that info from... as far as I'm aware, DeepMind Lab is definitely used in various publications (maybe primarily publications from DeepMind, but still). Considering the github repo has the GNU GPL 2 license, it also seems Open Source-friendly to me.

Another framework of which I'm sure that it would widely be considered suitable within academia would be the Unity ML-Agents Toolkit, which uses the Unity game engine.

I suppose you could also consider using ViZDoom, which is also used in various publications, but (as far as I'm aware) it only supports one specific game (Doom).

I do not have enough experience with using any of the above personally to be able to recommend one of them over the others... but they would all seem suitable to me.